The use of trenchless technologies is a relatively unexplored field of study in Slovenija, while their use is a common practice in many other countries. The thesis offers an insight into the possibilities for the use of trenchless technologies in the field of installation and rehabilitation of water mains in Slovenija. The focus in the first part of the thesis is mainly on the slovenian and dutch policy in the field of water supply and trenchless technologies. Also, we briefly discussed the technical information about slovenian and dutch water supply in order to better understand the reasons for their similarities and the differences. In the second part of the thesis the classification of the technologies for trenchless water pipe installation had been made as an alternative to the traditional open – trench installation. In addition, an overview of the technologies for the rehabilitation of water mains had been made. With the term rehabilitation we included cleaning, repairs, renewal and replacement of the water mains. The comparison between the rehabilitation technologies had been discussed as well. Third part of the thesis presents flowcharts for decision–making about the suitable technology for the rehabilitation of water mains. In the end we tested the use of flowcharts in four different water main locations.